I KNEW someone would catch that. I guesstimated the side of the
cross-hole in an effort to get the general idea across so someone who
knew about such bolts would pipe up.

I don't possess the tools to do this as well as it should do, and I
don't want to modify the existing bolt as it is a carriage head bolt and
the hole it goes into is round. I'm looking for the general name of this
type of bolt so I can see about sourcing a hex-head bolt for the job.

On Tue, 2011-05-24 at 21:33 -0400, David Beierl wrote:

> At 08:49 PM 5/24/2011, Alistair Bell wrote:
> >cut the bolt and drill a new hole...
>
> Better do it carefully.  Counting the depth of the thread you've got
> less than 1/32" of meat on either side of a 3/16" hole in a 5/16-18
> bolt.  .025 inches actually, assuming National Form threads (good
> assumption, I think).
>
> Suggest you a) grind a flat on the side of the bolt and b) use a
> smaller hole or better yet c) a larger bolt.  If you have to stick
> with 5/16, going to fine thread (24 tpi) will gain you nine thou on
> each side of the hole, for a total of .035 or the thickness of nine
> Post-It notes on each side instead of six-plus.
>
> Yrs,
> d